This invention relates to the method and apparatus for providing spatial coherency of an energy beam at a remotely located target.
In energy transmission systems such as laser transmitting arrangements, for example, atmospheric inhomogeneities and/or phase unbalances across the aperture feed system causes undesirable spreading of the transmitted beam at a remotely located target. One technique for improving the spatial coherency of the transmitted beam at the target is disclosed in U.S. Pat. No. 3,731,103 wherein the beam is processed by N subapertures with continuous phase control being effected on the radiation from each subaperture. Although the approach of the just cited patent is perfectly suitable for many applications, the subject invention which provides beam correction by means of direct optical compensation is thought to be particularly advantageous inasmuch as its resolution is not limited by an arbitrary number of phase correction elements and its implementation is generally less complex.